New build ... think this PSU would be able to hack it?

[capt_taco]

So I'm planning on building a new system in about December, so that my wife and I will have two decent gaming machines to use (she's also a gamer, and one or the other of us is always hogging the computer). However, I'm tempted to order a couple of parts now since they're on sale. Approximate specs of the system will be:

CPU: AMD 6-core
mobo: undecided
GPU: GTX 470 - also considering HD 5850 if the price is right
RAM: 2x2GB DDR3-1600 (ideally 7-7-7)
HDD: Seagate Barracuda 7200rpm 1TB (already own - got for $39.99!)
Monitor: 1920x1080 (already own)
DVD burner: LG 24X - $18.99 http://www.newegg.com/Product/Product.aspx?Item=N82E16827136177

The issue is this PSU - Thermaltake 500W, great deal at $29.99, but may be pushing it: http://www.newegg.com/Product/Product.aspx?Item=N82E16817153113

I think I ought to be OK on the overall wattage, though a little close ... it's the amps I'm worried about, at 25A on the first 12V rail and 18A on the other. Together that would be plenty, but my knowledge of what the configuration of the PSU will allow is admittedly less than stellar, and I don't want to end up overloading a single rail.

Other option would be to take the 850W PSU out of my existing machine (q9550, HD 4870) and replace it with the 500W job, then use the 850W one on the new build. That seems to me like it ought to work. I had a big PSU on that machine because I was considering crossfire, but never did it.

Also: Yes, I know this PSU is not Antec or Corsair. I'm fine with that. Thermaltake seems to stay out of the step-above-junk category that you want to avoid, so unless someone comes screaming advice to the contrary, I'd rather take this one instead of paying double or triple the price.

 

[COLGeek]

Since you are looking at a higher end GPU, I would recommend a beefier PSU. A couple bucks now may save you a few headaches later.

I would suggest one of these two PSUs:
http://www.newegg.com/Product/Product.aspx?Item=N82E16817371031
-or-
http://www.newegg.com/Product/Product.aspx?Item=N82E16817139005

Now, that being said, the one you picked will likely be okay in the short term, but you should weigh it against the cost of your GPU (especially if you fry it due to a less than good PSU).

Good luck!

 

[NeoElemental]

W = amps * volts, so you can see that you have 300w available on the 12v rail. Your gfx card and chip both run on the 12v rail. You should definitely bump up. 650 would be fine. I would go with the Corsair COLGeek posted, since it's at a great price.

If you're looking to step up to 750w, I would go with the XFX, since it's a tier 1 psu and cheaper than the other tier 1 options (corsair, seasonic)

 

[wielander]

Take a look at this combo with a OCZ ModXStream 600W Power supply and 4GB of DDR3 1600 8-8-8 Ram for $105.

http://www.newegg.com/Product/ComboDealDetails.aspx?ItemList=Combo.492806


The power supply obviously isn't as good of some of the other ones mentioned, but it's still a step above the Thermaltake one. Reviews I've seen don't seem to be too harsh on the 600W model; it has larger heatsinks than others and doesn't have any problems handling the full 600W. It's also 80 Plus certified (almost Bronze) and modular.

You might be able to get the memory down to 7-7-7 timings with more voltage; you certainly won't find a better price for memory and a PSU together.

 

[capt_taco]

Take a look at this combo with a OCZ ModXStream 600W Power supply and 4GB of DDR3 1600 8-8-8 Ram for $105.

http://www.newegg.com/Product/ComboDealDetails.aspx?ItemList=Combo.492806


The power supply obviously isn't as good of some of the other ones mentioned, but it's still a step above the Thermaltake one. Reviews I've seen don't seem to be too harsh on the 600W model; it has larger heatsinks than others and doesn't have any problems handling the full 600W. It's also 80 Plus certified (almost Bronze) and modular.

You might be able to get the memory down to 7-7-7 timings with more voltage; you certainly won't find a better price for memory and a PSU together.

Now THAT is a good deal, considering that the RAM alone would normally come close to that price. If I can get it faster by OC'ing, great, if not, oh well, 8-8-8- is close enough. I don't mind OCZ for the power supply either; I know that both they and Thermaltake are kind of on the "B" list, not the "A+" list as far as PSUs go, but in my experience that's always worked out fine as long as you avoid the D-minus no-name brands that seem to be everywhere.

My question about the rails still stands with this PSU, though, since the 12V rail is split. According to the power consumption data I can find, the GTX 470 can suck up ~370W at full load, which is just over 30A. This PSU has two 25A rails, which (like the Thermaltake) would be enough together but not alone. I am just not sure whether the PSU's configuration will allow it. Can I distribute the load over both rails, or is that not going to fly? I haven't had to deal with this issue for a long time, as with most machines I've built until now, I've generally had either a PSU with a single big 12V rail, or a GPU that wasn't going to push the limits regardless of rail distribution.

It still seems to me that if this wouldn't work, my Plan B would be OK -- swapping this 600W PSU for the 850W one on my existing machine. The 4870 isn't going to use all 25A in any case. But of course, I am looking for people to punch holes in my theory before I buy.

 

[NeoElemental]

Quoted from a newegg review:


Nvidia 470 Req. Power: Minimum of a 550 Watt power supply. (Minimum recommended power supply with +12 Volt current rating of 38 Amps.)

PSU Output: +3.3V@25A,+5V@25A,+12V1@25A,+12V2@25A,
-12V@0.3A,+5VSB@2.5A

Is the 12V@25A a concern? Shouldn't the amps be at 35 to meet the cards min requirements?

Manufacturer Response:

Hello, video card recommendations take into consideration the power load for your entire system. Based on that figure you should be fine with one video card. If you have any further questions, please visit our support forums at the link below
Thank you

External Link(s):
OCZ Support Forums|


I don't know exactly how the draw would work, but other commenters on this forum and others seem to have been able to have it run stably without much of an issue (unless you get a bad unit, of course). Google "gtx 470 on ocz 600w" for more info.

 

[wielander]

The motherboard delivers the first 75 watts of power to a graphics card through the PCI-E connector. I think that ~370W figure is for a whole system. It can't be right for a stock GTX 470. It drew no more than ~250W when anandtech tested it:

http://www.anandtech.com/show/2977/nvidia-s-geforce-gtx-480-and-gtx-470-6-months-late-was-it-worth-the-wait-/19

Here is a review of the ModXStream 600W power supply.

http://translate.google.com/translate?js=n&prev=_t&hl=en&ie=UTF-8&layout=2&eotf=1&sl=de&tl=en&u=http%3A%2F%2Fwww.technic3d.com%2Farticle-820%2C6-ocz-600w-modx-stream-pro-netzteil-im-test.htm

It can handle a spike of more than the rated 25A on a rail (up to 35A). I saw a different article that was more thorough and came to the same conclusion, but I can't find it.

 

[NeoElemental]

The OCZ should be treated more like a 550w psu, not a 600w. That being said, I still think you'd be fine.

 

[wielander]

The OCZ should be treated more like a 550w psu, not a 600w. That being said, I still think you'd be fine.

Why do you think it should be treated like a 550w psu?

The fatal1ty 550W is basically the same power supply, but both can handle 600W easily. They are completely different builds than the ModXStream 500W and some of the other poor quality OCZ power supplies. I haven't seen any bad reviews of them. In that review it was 82% efficient at full load, and stable up to over 700Watts (at which point the overload circuit kicked in). They are ranked #2 on the power supply charts, only 1 step down from the best of the best.

It is kind of limited by the number of PCI-E connectors it has, but that is normal in the 600W range.

I don't think you should measure a power supply by the brand that is reselling it.

 

[dndhatcher]

Nvidia 470 Req. Power: Minimum of a 550 Watt power supply. (Minimum recommended power supply with +12 Volt current rating of 38 Amps.)

PSU Output: +3.3V@25A,+5V@25A,+12V1@25A,+12V2@25A,
-12V@0.3A,+5VSB@2.5A

Is the 12V@25A a concern? Shouldn't the amps be at 35 to meet the cards min requirements?

Most PSUs do not have purely split rails. They distribute the amperage over more than one rail somehow.

Look at the wattage chart for the 600. It has 2 rails at 25A each, but a combined max wattage of 504 on the 12V rails. 504/12 = 42 amps combined max. If the rails were truly distinct, which I have only seen on a few PSUs, the wattage chart would show them with individual wattages of 300W.
http://www.ocztechnology.com/images/awards/mxsp_wattage_charts.jpg

 

[capt_taco]

The motherboard delivers the first 75 watts of power to a graphics card through the PCI-E connector.

Duh. I was not even figuring that in, and it makes all the difference in this case. That by itself ought to solve the problem.

I think that ~370W figure is for a whole system. It can't be right for a stock GTX 470. It drew no more than ~250W when anandtech tested it:

http://www.anandtech.com/show/2977/nvidia-s-geforce-gtx-480-and-gtx-470-6-months-late-was-it-worth-the-wait-/19

I was going by the highest case I could find, which was this: http://www.tomshardware.com/reviews/geforce-gtx-480,2585-15.html

However, it looks like the problem there is that they're using Furmark, so it's perhaps an inflated figure. Another thing that I suppose I was worrying too much about.

Yeah, overall, I think that OCZ unit is going to work, and the combo is easily the best deal out there. Good stuff.

 

[NeoElemental]

Reviews that I've seen show less than stellar efficiency and ripples at the full 600w, which is why I guess people say that it's more like a 550w psu. Of course it can run above the 550, or 600 for that matter, but it loses it's stability/efficiency.

Aside from the formal reviews, I've seen enough anecdotal evidence about the ocz 600w modxstream specifically that I would always just pony up the extra $30 for a better quality psu. There's a reason this psu is always in combo deals...

 

[capt_taco]

Best answer selected by capt_taco.

 

[capt_taco]

Take a look at this combo with a OCZ ModXStream 600W Power supply and 4GB of DDR3 1600 8-8-8 Ram for $105.

http://www.newegg.com/Product/ComboDealDetails.aspx?ItemList=Combo.492806

This is what I ended up doing, by the way. That deal was just too good to pass up. Parts got here yesterday, which reminded me of this thread.

 

[Mousemonkey]

This topic has been closed by Mousemonkey